Affiliations: Faculty of System Design, Tokyo Metropolitan University, Tokyo, Japan | Research Institute, National Defense Medical College, Saitama, Japan | Aeromedical Laboratory, Japan Air Self-Defense Force, Saitama, Japan | Department of Surgery, National Defense Medical College, Saitama, Japan | Department of Health Crisis Management, National Institute of Public Health, Saitama, Japan | Department of Global Infectious Diseases and Tropical Medicine, National Defense Medical College, Saitama, Japan
Note: [] Address for correspondence: Masayuki Ishihara, PhD, National Defense Medical College, Research Institute, 3-2 Namiki, Tokorazawa, Saitama, 359-8513 Japan. Tel.: +81 429 95 1211; Fax: +81 429 91 1611; E-mail: ishihara@ndmc.ac.jp
Abstract: We previously reported a simple method for the preparation of size-controlled spherical silver nanoparticles (Ag NPs) generated by autoclaving a mixture of silver-containing glass powder and glucose. The particle size is regulated by the glucose concentration, with concentrations of 0.25, 1.0 and 4.0 wt% glucose providing small (3.48±1.83 nm in diameter), medium (6.53±1.78 nm) and large (12.9±2.5 nm) particles, respectively. In this study, Ag NP/chitosan composites were synthesized by mixing each of these three Ag NP suspensions with a 75% deacetylated (DAc) chitosan suspension (pH 5.0) at room temperature. The Ag NPs were homogeneously dispersed and stably embedded in the chitosan matrices. The Ag NP/chitosan composites were obtained as yellow or brown flocs. It was estimated that approximately 60, 120 and 360 μg of the small, medium and large Ag NPs, respectively, were maximally embedded in 1 mg of chitosan. The bactericidal and anti-fungal activities of the Ag NP/chitosan composites increased as the amount of Ag NPs in the chitosan matrix increased. Furthermore, smaller Ag NPs (per weight) in the chitosan composites provided higher bactericidal and anti-fungal activities.
